Space Transportation - mmmt_transportation.pdf - Moon Society

MMM #124 - April 1999
Man-rated Mass Drivers & Mass Catcher to & from Lunar Orbit
By Peter Kokh
In a previous article [MMM #121 DEC ‘98, “Lunar Intercity ‘Flights’ via the INTERCHUTE”] we sketched an idea
for electromagnetic man-rated mass-driver / mass- catcher pairs to handle high volume inter-settlement passenger
traffic on the Moon via an automated suborbital shuttle system. Here we sketch the use of a similar system to get
people on and off the Moon cheaply and safely - once an expensive infrastructure is discounted or amortized. As with
the suborbital Interchute, this is a trick difficult to match on Mars where atmospheric interference
would make it impossible to compensate with enough precision to make it work safely.
Unlike the “Interchute” system in which each electromagnetic cannon will both throw and catch, for to/from
orbit traffic, as the directions (to/from) are opposite, not the same, there will need to be two cannons, one doing all
the throwing, the other all the catching. It would be convenient to line them up back to back with a passenger terminal
building in between. That would make it handy to process a shuttle that has just arrived for the return flight to space.
Several parking slips would be needed, as the order of arrival is certain not to be observed in the order of departure.
! As traffic at this electromagnetic space port (ESP) grows, more parking slips will have to be added and
provision for such expansion should be made in the original design.
Parking is likely in a sky-sheltered area exposed to the vacuum. Nominal service can then be done in soft
suits. Pressurized garages would be available for more labor-demanding service. Since the various craft would need to
have the same diameter and cylindrical cross-section, this would make a standard garage slip-lock a sure thing.
The stakes are high. It would require corresponding space infrastructure, either in a precisely positioned orbit
and oriented orbit, or near L1 or L2 Earth-Moon Lagrange points, whichever is the more stable and forgiving. It would
also require onboard propulsion to taxi to the shifting station from its driver-catcher trajectory path and vice versa.
• If the space transfer station is to be at L2, behind the Moon, the ESP would need to be sited on the Nearside
Equator.
• If the space station is at L1, between Earth and the Moon, the ESP would have to be built on the Farside Equator
in an intercrater plain - there are no maria smack on the Farside equator (a mare fill area in Aitken crater is
the closest match), unlike the Nearside situation where there is an abundance of potential sites.
• Either option poses problems for the maintenance of the priceless Farside radio silence needed by radio
astronomers and the S.E.T.I. Project. It would be near impossible to reproduce this radio silence anywhere
else in the Solar System
A potential disadvantage is that a driver-catcher must be on the equator - precisely so - whether handy or not
to the locations of existing settlements. On the other hand, such an installation would be an economic boon to any
settlements nearby or surely give rise to one if there were not.
The installation of such an ESP facility would speed up of the flow of immigration to the Lunar Frontier
Territory (or Republic) as well as lower the cost per individual. A same cross-section, same total weight range cargo
hold craft would greatly lower the cost of importing and exporting large items. In both ways, the inauguration of such
a facility would mark a threshold of significant expansion of the lunar economy in total trade volume, tourist volume,
and settled population. Inauguration of service will mark the attainment of a critical mass that changes the prospectus
of the lunar frontier substantially.
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